JPS62222264A - Method for developing electrophotograph - Google Patents

Abstract

PURPOSE:To obtain a good image by using an electrophotographic developing method providing the inside of a sleeve with a rotary magnet roll, holding a magnetic brush and an image-forming body out of contact with each other, and satisfying a specified algebraic expression. CONSTITUTION:A latent image is developed on the image-forming body by forming a magnetic brush composed of the carrier and the toner of a binary developer on a sleeve and applying the electrophotographic developing method satisfying algebraic expressions I and II, where Vsl is the linear velocity of a developer carrying body (sleeve), n is the number of the magnetic poles of a magnetic roll, omegam is the rotative angular velocity of the magnetic roll, h is the length of the magnetic brush, Vd is the linear velocity of the image- forming body, mt is an amount of toner attached to said sleeve, Vsl and omegam are positive when they move in the direction same as that of the image-forming body, thus permitting the obtained image to be made sufficient in density and good in resolution, and free from any noise by using a developer layer composed of a short magnetic brush.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a developing method for copying machines, printers, etc. using electrophotography.

[Background of the Invention] Conventionally, as a method for developing a latent image on an image forming body in an electrophotographic copying apparatus, etc., there are two methods: one uses a one-component developer that imparts magnetism to the toner itself and eliminates the need for a carrier, and the other uses a non-magnetic or non-magnetic developer. A two-component developer consisting of a slightly magnetic toner and a magnetic carrier is sometimes used, but the latter allows easy control of toner friction and provides excellent developability. It is widely used because it has the feature of being able to impart any color to the toner.

In order to further improve the image quality of the obtained image, the present applicants have proposed a method of developing with a two-component developer without directly rubbing the latent image surface (for example, JP-A-59-1
81362). Another major feature of this method is that it can be applied to multicolor development (for example, JP-A-60
-76766).

[Problems to be Solved by the Invention] In this developing method, the magnetic brush formed on the developer conveying member (hereinafter referred to as sleeve) is separated from the latent image surface, that is, there is no contact. Electrostatic force due to the fine pattern is less likely to act on the toner to be developed. The resulting image has a problem in that the reproducibility and resolution of fine lines are insufficient, and fine patterns cannot be expressed.

In order to solve this problem, the applicant first formed a developer layer consisting of extremely short magnetic brushes on the sleeve,
We proposed a method for non-contact development by reducing the distance between the image forming body and the sleeve (hereinafter referred to as the development gap) (Japanese Patent Application No. 6O-192710).

According to this method, the electric field generated in the development area is strong;
and becomes finer, and the above problem is solved.

However, the amount of toner transported to the development area is reduced,
The developer density tends to be insufficient.

To compensate for this, there is a method of increasing the rotational speed of the sleeve, but since the toner moves with a velocity component parallel to the latent image surface, the sharpness of the image edges is affected by the directionality. appear. For example, the leading or trailing edge of a character is missing. Such an image not only lacks information but also gives an extremely unsightly impression, making it unsuitable for practical use. Further, even if a strong alternating current bias is applied to the sleeve, the developed density does not increase and only fogging occurs.

The present invention aims to solve the above problems by focusing on the movement of the magnetic brush formed on the sleeve, and it is possible to achieve sufficient density and good resolution even with a developer layer consisting of short magnetic brushes. The purpose of the present invention is to provide a method for developing images without noise.

[Means for Solving the Problems] The purpose is to form a magnetic brush of a two-component developer consisting of carrier and toner on a developer conveying member, thereby developing a latent image on an image forming member. An electrophotographic developing method, characterized in that the developer conveying body has a rotating magnetic roll therein, the magnetic brush and the image forming body are kept in non-contact, and the following formula is satisfied: Yes, it will be achieved.

Here, Vsi is the linear velocity of the developer conveying member, n is the number of magnetic poles of the magnetic roll, ωm is the rotational angular velocity of the magnetic roll, h is the length of the magnetic brush, "J (I is the linear velocity of the image forming member, mt
represents the toner adhesion per unit area of the developer conveying member. Vsi and ωm are positive when they are in the same direction as the movement of the image forming body. Further, the length of the magnetic brush refers to the average length of the magnetic brush on the sleeve, which stands on top of the magnetic pole in the sleeve.

[Operation] FIG. 1 is an example of a developing device in which the present invention can be practiced. In the figure, 1 is an image forming body having a photosensitive layer, 2 is a housing, 3 is a sleeve, 4 is an N magnetic roll having 83 poles, 5 is a member, 6 is a fixing member for the member, 7 is a first stirring member, 8 is a second stirring member. Reference numerals 9 and 10 indicate the rotating shafts of the agitating members 7 and 8, h indicates a replenishment toner container, 12 indicates a toner supply roller, 13 indicates a developer reservoir, 14 indicates a developing/curing assemblage source, and 15 indicates a developing area, ie, a sleeve conveyed. A region where toner can be transferred to the image forming body under electrostatic force, T represents toner, and D represents developer. In this developing device, the developer pool in the developer reservoir 13 is sufficiently agitated and mixed by the first stirring member 7 rotating in the direction of the arrow and the second stirring member 8 rotating in the opposite direction so as to overlap with each other. , due to the conveying force of the sleeve 3 rotating in the direction of the arrow ITT and the magnetic roll h rotating in the opposite direction of the arrow ■,
It adheres to the surface of the sleeve 3 and is transported in the direction of the arrow (■). A layer forming member 5 held by a fixing member 6 extending from the housing 2 is pressed against the surface of the IJ-pool 3 to regulate the amount of developer to be conveyed and form a developer layer.

When a developer layer was formed on this sleeve 3 under appropriate conditions and the sleeve surface was observed under a microscope, it was found that many magnetic brushes with an average length of 300 μm stood directly above the magnetic pole of the magnetic roll without touching each other. was. FIG. 2 is an enlarged sectional view of the vicinity of the sleeve surface, showing this situation.

When the magnetic roll 4 is rotated in this state, the magnetic roll 4
It was observed that the developer moved as each magnetic brush rotated in a direction opposite to the direction of rotation of the magnetic brushes. The moving speed was about 40 mm/S when the rotational speed of the magnetic roll was 500 r, p, m. The number of magnetic poles is 8 as shown in the figure.
It is extreme. Further, the moving speed of the developer was approximately proportional to the rotational speed of the magnetic roll. From the above results, the moving speed of the developer due to the rotation of the magnetic roll is expected to be nIJJmh/3 (symbols are as described above).

on the other hand,? When the magnetic roll 4 of the developing device shown in FIG.
When si/Vd exceeded 10, the directionality of development as described above was noticeable.

By analogy with the above experimental results, we rotated the magnetic roll and sleeve and developed under the following conditions. As shown in the following examples, in all cases the sharpness of the leading and trailing edges was An image with no difference was obtained.

Next, we focused on the fact that sufficient toner must be conveyed to the development area in order for development to be carried out satisfactorily, and development was carried out under conditions that satisfied the following. As a result, if the above conditions are not met, no matter how you set other conditions,
On the other hand, under the above conditions, a practically sufficient developed density was obtained by (1) applying an alternating current bias to the sleeve, (2) reducing the developing gap, etc.

Note that, assuming practical development conditions and considering development efficiency, etc., it is preferable to use the following range, and furthermore, in order to ensure that the development process is performed once and the image quality is satisfactory, it is desirable to keep it within the range of .

A method for forming a thin developer layer, that is, a short magnetic brush, on the sleeve 3 in the developing device shown in FIG. 1 will be described in detail.

FIG. 3(a) is a diagram showing the main parts of the layer forming section. The developer is conveyed in the direction of arrow Da by rotation of the sleeve 3 or the like. When the developer reaches the tip of the layer regulating member 5, it is divided into those that pass through the gap between the layer regulating member 5 and the surface of the sleeve 3 and those that are carried above the layer regulating member 5 without passing through the gap. . Only the former can reach the development area.

Therefore, the size of the gap, that is, the layer regulating portion (4
There is a close relationship between the distance between the tip of the sleeve and the sleeve (hereinafter referred to as h) and the amount of developer conveyed.

FIG. 3(b) shows the experimental results, with the horizontal axis representing the gap I and the vertical axis representing the density of the amount of developer deposited on the sleeve. This data was obtained from the amount of developer collected by applying adhesive tape to the sleeve surface, and other conditions were set appropriately.

It can be seen from the figure that when this gap exceeds a certain value, the amount of developer on the sleeve is stable against these changes. In this stable state, the toner necessary for the above-mentioned development can be sufficiently transported.

Other experiments have shown that the length of the magnetic brush formed changes little over time, and that room temperature and other parameters have little effect on the appearance of this steady state.

Therefore, if the gap at the tip is set to 0.08 mm or more,
The mounting can stably transport a certain amount of toner despite variations in precision and mechanical precision.

Furthermore, it was found that it is preferable to set the gap at the tip to 0.1 mm or more because stability increases. Of course, it is not desirable to make the gap between the tips unnecessarily large, and it has been observed that when the gap is increased to 5 mm or more, the uniformity of the developer layer formed by the magnetic brush is disrupted.

When the developer layer is formed under such conditions, impurities in the developer, aggregates of carrier or toner, etc. cannot pass through the regulation position, and the developer layer reaching the development area is always uniform and stable.

Other means for forming the developer layer when carrying out the present invention include, for example, a magnetic or non-magnetic regulating plate placed apart from the sleeve with a certain gap, a magnetic roll placed close to the sleeve, etc. Any conventionally known method may be used. It is advantageous for the carrier and toner constituting the developer to have small particle diameters from the viewpoint of image quality resolution and gradation reproducibility.

For example, even when the carrier in the developer layer has a small particle size of 30 μm or less, by using a means such as the layer forming member 5 described above, impurities and agglomerates in the developer can be automatically removed and a uniform length can be obtained. A magnetic brush can be formed. Furthermore, even when the carrier has a particle size as small as that of the toner, contamination of impurities is similarly eliminated and a magnetic brush of uniform length can be formed.

A perspective view and a front view showing the specific structure of the stirring members 7 and 8 incorporated in the developing device shown in FIG. 1 are shown in FIGS. 1(A) and 1(B). In the figure, 7a, 7b, and 7c are the stirring blades of the first stirring member, and 8a, 3b-, and 3c are the stirring blades of the second stirring member, and there are various types such as square plate blades, disc blades, and clear disc blades. , respectively rotation axes 9 and 10
are fixed at mutually different angles and/or positions. The two stirring members 7 and 8 are configured so that the stirring areas overlap without the stirring blades colliding with each other, so that sufficient stirring in the left and right direction (Fig. 1) is performed, and the stirring plate Because of the inclination (FIG. 4(A)), sufficient stirring in the front-back direction (FIG. 1) is also performed.

Further, the toner T supplied from the hopper h via the supply roller I2 is also uniformly mixed into the developer solution in a short time.

Although carrier and toner having small particle diameters as described above are difficult to mix in the conventional technology, the stirring means shown in FIG. 4 mixes them sufficiently due to the above-described action. However, it goes without saying that the present invention is not limited to this.

Next, the composition of a preferable developer used in the developing method of the present invention will be described.

An example of the structure of the toner is as follows.

■ Thermoplastic resin (binder) 80~qQ wt Example: polystyrene, styrene acrylic polymer, polyester,
Polyvinyl butyral, epoxy resin, polyamide resin, polyethylene, ethylene-vinyl acetate copolymer, etc., or a mixture of the above ■ Pigment (coloring agent) 0-15 wt% Example: Black: Carbon black Yellow: Benshicine derivative Magenta: Rhodamine B lake, Carmine 6B, etc. Noan: Phthalocyanine, sulfonamide derivative dye, etc.■ Charge control agent O-5wt plastoner dinigrocyanine-based electron-donating dye, alkoxylated amine, alkylamide, chelate, pigment, quaternary ammonium salt, etc. Minus toner: Electron-accepting organic complex, chlorinated paraffin, chlorinated polyester, polyester with excess acid groups, chlorinated copper phthalocyanine, etc. ■ Examples of fluidizing agents: Colloidal silica, hydrophobic 7-liquid, silicone varnish, metal soap , nonionic surfactants, etc.■ Cleaning agents (prevents toner film-forming on the photoreceptor) Examples: fatty acid metal salts, silicon oxides and silica acids with organic groups on the surface, fluorine surfactants, etc. ■ Fillers ( (Improvement of image surface gloss, reduction of raw material costs) Examples: Calcium carbonate, clay, Merck, pigments, etc. In addition to these materials, a small amount of magnetic powder may be included to prevent fogging on the image surface and toner scattering. .

As such magnetic powder, triiron tetroxide, r-ferric oxide, chromium dioxide, nickel ferrite, iron alloy powder, etc. with branch threads of 0.1 to 1 mm are used, and 0.1 to 5 wl %
Contains. In addition, in order to make the color tone of the toner clear, especially the color tone, the magnetic powder may be included.
It is desirable to set it to t% or less.

In addition, resins suitable for pressure fixing toners that are plastically deformed and fixed to paper by a force of about 201 (g/CTL) include waxes, polyolefins, ethylene-vinyl acetate copolymers, polyurethanes, adhesive resins such as rubber, etc. is used.

A toner can be made using the above-mentioned materials by a conventionally known manufacturing method.

In this apparatus, in order to obtain a more preferable image, the toner particle size (weight average) is 5o/1ma degree or less, especially 15o/1ma degree or less.
It is preferable to set it to ltm. If it exceeds 15 μm, the image quality will be poor, if it exceeds 5Q ltm, the fine print will become hard to read, and if it is less than 1 μm, fog will occur and the sharpness of the image will be lost. Note that the particle size or average particle size of the toner and carrier as used in the present invention means a weight average particle size, and the weight average particle size is a value measured with a Coulter Counter (manufactured by Coulter Inc.). Also, the specific resistance of the particles is 0.
．． Volume 8 with a cross-sectional area of 50i: After putting the packed particles in a container and tapping, a load of +ky/d is applied on the packed particles to make the thickness about 1 mm, and between the load and the bottom electrode there is a It is determined from the current value that flows when an electric field of IO'V/cm is generated. The composition of the carrier is as follows, and basically the materials listed as the constituent materials of the toner are used.

The carrier particles are mainly composed of magnetic particles and resin, and in order to improve resolution and gradation reproducibility, they are preferably spherical and have a weight average particle diameter of 50 μm or less, especially 5 μm or more and 40 μm. ] The following are preferred. If the carrier particle diameter exceeds 7108 m5, particularly 50 μm, the magnetic brush becomes long and rough, making it difficult to realize a thin developer layer, resulting in poor developability and poor image quality. Moreover, if it is less than 5 μm, the developability, triboelectric chargeability, and fluidity of the developer will be poor, and carrier scattering will occur.

In addition, in order to prevent charges from being injected by the bias voltage and carriers from adhering to the surface of the image forming body and from dissipating the charges that form a latent image, the resistivity of the carrier is set to 108Ω.
It is preferable to use an insulating material having an insulating value of 1013 Ω or more, preferably 1013 Ω or more, more preferably 1014 Ω or more.

Such a carrier is made by coating the surface of a magnetic material with a resin, or by dispersing magnetic particles in a resin, and selecting the resulting particles using a known particle size selection means.

Further, when the carrier is to be made into a spherical shape, it is carried out as follows.

■Resin-coated carrier: Select spherical magnetic particles.

■Magnetic powder dispersed carrier After forming the bi-dispersed resin, a spherical shape treatment is performed using hot air or hot water, and then a spherical dispersed resin is directly formed by a spray drying method.

It is preferable to mix the toner and carrier described above in such a ratio that the total surface area of each toner is equal.

For example, the average particle size of toner is 10 μm5 specific gravity is 1.2 g/
crI, average particle size of carrier is 35 μm, specific gravity is 4.5
I/crtr, the toner strength (weight ratio of toner to developer) is 2 to 30 W+%, preferably 5 to 30 W+%.
It is appropriate to set it to +5 wt%. If the toner concentration is lower than the above range, it will be difficult to transport the toner sufficiently and the amount of charge will become too high.
Sufficient development is not performed. Furthermore, when the toner concentration exceeds the above range, the toner is insufficiently charged and easily separates from the carrier, resulting in a serious problem of dirt inside the machine due to toner scattering.

[Example] The present invention will be specifically explained below using Examples, but the embodiments of the present invention are not limited thereto.

(Example 1) FIG. 5 is a sectional view of a main part of an image forming apparatus explaining this example. In the figure, 1 is an image forming body rotating in the direction of the arrow, 21 is a corona charger, L is image exposure, 22 is a developing device having the same structure as in FIG. 1, 32 is a pre-transfer exposure lamp, 33 is a transfer electrode, Reference numeral 34 denotes a separation electrode, p a transfer paper, and 35 a cleaning static eliminator comprising a static eliminator electrode 35a and a static eliminator rung 35b.

3G is a cleaning device with cleaning blade 36
a and a bias roller 36b.

Image formation is performed in this apparatus as follows. After the surface of the image forming body 1 is charged with a uniform potential by the corona charger 21, image exposure I. is performed to form a latent image. This latent image is developed by the developing device 22 under conditions described later to obtain a toner image. After this toner image is uniformly exposed by the pre-transfer exposure lamp 32, it is transferred onto the conveyed transfer paper P at a predetermined timing by the action of the transfer pole 33, and the transfer paper P is imaged by the action of the separation pole 34. The toner image separated from the forming body 1 and further transferred by a fixing device (not shown) is fixed onto the transfer paper P and discharged to the outside of the machine.

On the other hand, the surface of the image forming body 1 after being transferred is exposed to the elimination electrode 35a of the pre-cleaning static elimination device 35 and the static elimination lamp 35.
After being neutralized by b, the toner is cleaned by the blade 36a of the cleaning device 36, and the toner that spills out at this time is applied to the bias roller 3, which rotates.
Uke is stopped by 6 b.

Note that image exposure is performed by a semiconductor laser with a wavelength of 780 nm.

Next, the developer used will be explained.

The toner is produced as follows.

Polyester resin + 20p 100 parts by weight (
Polypropylene 660p 6p (manufactured by Sanyo Chemical Industries, Ltd.) Carbon black Mogul LIQ // (manufactured by Cabot Corporation) were mixed in a Henschel mixer, and then thoroughly kneaded at a temperature of 140°C with three rolls. The average particle size is reduced to 10 μ by the process of cooling, coarse pulverization, jet mill pulverization, and classification.
m colorant particles are obtained. 0 parts of hydrophobic fine silica R-812 (manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts by weight of the colorant particles.
．． A toner is obtained by adding 4 parts by weight and dispersing and mixing in a type mixer.

The main physical properties of this toner include resistivity of approximately 1014Ω,
The average particle diameter is 10 μm, the specific gravity is 1.2, and the ratio is '7/i.

The carrier is produced as follows.

Spherical manganese-zinc ferrite particles (1' manufactured by DK) were coated with styrene on the particle surface using a spira coater.
A carrier is obtained by coating with acrylic resin to a thickness of 1.5 μm. The main physical properties are that the average particle size is 30 μm, the resistivity is about 1013 Ω, the magnetization is 85 emu/d, and the specific gravity is 4.6 g/crIi.

A desired developer is obtained by mixing 10 parts by weight of such toner with 90 parts by weight of carrier. If this is sufficiently stirred, the average charge amount of the toner will be about -20 μC/1.

Other image forming conditions are summarized in Table 1.

The average length of the magnetic brushes formed on the surface of the sleeve is 250 μm when observed with a microscope.

When the toner was applied to the low potential (exposed) portion of the image forming body and developed under the following conditions, an image with sufficient density, good resolution, and no directionality was obtained.

Next, when the rotational speed of the sleeve was changed and development was performed, directionality appeared when the sleeve linear speed reached about 420 mm/s, and became noticeable at about 550 mm/s or higher. Furthermore, when the linear velocity of the sleeve was lowered to 79 mm/s or less, it became increasingly difficult to increase the density. Further, when the linear velocity of the sleeve was 250 mm/s, the rotation speed of the magnetic roll was varied from 0 to 1500 r, p, m, and the direction of rotation was further changed for development.

As a result, sufficient image density can be obtained in both cases.
Almost no directionality of development appeared.

(Example 2) Image formation was performed using the image forming apparatus shown in FIG. 5 in the same manner as in Example. The toner used in Example 1 was used, and the carrier prepared as follows was used.

Styrene-acrylic resin (monomer composition ratio of styrene, butyl acrylate and methyl methacrylate 75:15:10
) 50 parts iron base metal (I'e 98% by weight, Si 2% by weight, saturation magnetization strength 190 emu/Ji')
50 parts Charge control agent "Nigrosine SO" (manufactured by Orient Chemical Co., Ltd.) 2 or more parts of the substance are mixed in a ball mill, further kneaded with two rolls, and then pulverized and classified.

The main physical properties of such carriers are that the average particle size is 30
The resistivity of blood is about 1014Ω, the specific gravity is 2.4E/d,
The magnetization strength is 60 emu/i.

These toners and carrier are mixed at a weight ratio of 3 to obtain a desired developer. When this is thoroughly stirred, the amount of charge on the toner is approximately -201LC/, on average! It became 7.

The other difference from Example 1 is that the development gap was set to 600μ.
The amount of toner adhesion on m1 sleeve is 0.6m9/c! ! This is what happened. As a result, the average length of the magnetic brush formed on the sleeve was 200 ttm.

When the toner was applied to the low potential portion of the image forming member and developed under the above conditions, a high quality image without directionality was obtained with sufficient immersion.

(Example 3) The present invention was implemented using a multicolor image forming apparatus as shown in FIG. The principle will be explained using the flowchart shown in FIG. 7th
The figure shows changes in the surface potential of the image forming body, and p
tT is the exposed area of the image forming body, DA is the unexposed area of the image forming body, and DUI' is the toner rl in the exposed area p[-3 in the first development.
It shows the increase in potential caused by the attachment of Nl. For the sake of explanation, the polarity of the latent image is assumed to be positive.

(2) The image forming body is uniformly charged by a charger and has a constant positive surface potential E.

(2) First image exposure is applied using an exposure source such as a laser, cathode ray tube, or LUD, and the potential of the exposed portion pI-T decreases in accordance with the amount of light.

(2) The electrostatic latent image thus formed is developed by a developing device to which a positive bias approximately equal to the surface potential E of the unexposed area is applied. As a result, the positively charged toner T adheres to the exposed portion p)I, which has a relatively low potential, and a first toner image is formed. The area where this toner image is formed is positively charged toner Tl'l.

As a result of the adhesion, the potential increases by r)UP, but
Normally, it does not have the same potential as the unexposed area r)A.

■ Next, the surface of the image forming body on which the first toner image has been formed is charged a second time by a charger, and as a result, the toner T
Regardless of the presence or absence of , a uniform surface potential E is obtained.

(2) A second image exposure is performed on the surface of this image forming body to form an electrostatic latent image.

(2) Similarly to (2) above, the positively charged toner T2 having a different color from the toner T and (2) is developed to obtain a second toner image.

Thereafter, the same process is repeated as many times as necessary to form a multicolor toner image on the image forming body. A multicolor recorded image is obtained by transferring this to a transfer material 2 and further fixing it by heating or applying pressure. In this case, the toner and charges remaining on the surface of the image forming member are cleaned and used for the next multicolor image formation.

The multicolor image forming apparatus shown in FIG. 6(a) operates as follows. 1 (lii) The image input unit IN includes an illumination light source 16, a mirror 20, a lens 2; 3, and a -dimensional color CCD image sensor 24.
are integrated into a unit, and the image input section IN
is moved in the direction of arrow X by a small device (not shown),
flCr) The image sensor 24 reads the original.

The image information read by the image input section IN is sent to the image processing section T.
R is used to convert the data into data suitable for recording.

The laser optical system 26 forms a latent image on the image forming body 1 in the following manner based on the above two-dimensional data, and this latent image is fully developed to form a toner image on the image forming body. . The surface of the image forming body 1 is uniformly charged by a scorotron charging electrode 21. Subsequently, the image forming body 1 is irradiated with image exposure light from the laser optical system 2G via the lens in accordance with the recorded data. In this way, an electrostatic latent image is formed. This electrostatic latent image is developed by a developing device A containing yellow toner. This developing device A has the same structure as that shown in FIG.

The image forming body on which the toner image has been formed is uniformly charged again by the scorotron charging electrode, and subjected to image exposure according to recorded data of another color component. The formed electrostatic latent image is developed by a developing device B containing magenta toner. As a result, a two-color toner image of yellow toner and magenta toner is formed on the image forming body 1. Thereafter, the cyan toner and the black toner are developed in a similar manner, and a four-color toner image is formed on the image forming member I. Note that the developing devices A, B, C, and D that accommodate the toners of each color have the same structure as the developing device shown in FIG.

The multicolor toner image thus obtained is exposed to the exposure lamp 3.
2, the transfer pole 33 is removed and transferred easily.
The image is transferred onto the recording paper P by the following steps. Recording paper P has separated poles 3/1
The image is separated from the image forming body 1 by the image forming member 1 and fixed by the fixing device 31 . On the other hand, the image forming body 1 is cleaned by the removing electrode 35 and the cleaning device 36.

The cleaning device 36 includes a cleaning blade 36a and a fur brush 36C. These are kept out of contact with the image forming body 1 during image formation, and when a multicolor image is formed on the image forming body 1, they come into contact with the image forming body 1 after the transfer.
Scrape off any residual toner. Thereafter, the cleaning blade 36a leaves the image forming body 1, and a little later, the fur brush 36c leaves the image forming body 1. fur brush 3
6C functions to remove toner remaining on the image forming body 1 when the cleaning plate 36a is separated from the image forming body 1. 36b is a roller that collects the toner scraped off by the blade 36a.

The laser optical system 26 is shown in FIG. 6(b). In the figure, 37
is a semiconductor laser oscillator, 38 is a rotating polygon mirror, and 39 is a
It is a θ lens.

The carrier used here was the same as in Example 1.

In addition, the toner is the same black toner as in Example 1,
In other toners, each colorant was used in place of carbon black. In other words, yellow toner contains auramine,
In the magenta toner, copper phthalocyanine is used in the Rhodamine B1 cyan toner. The mixing ratio of toner and carrier was 1:9 (weight ratio). Other imaging conditions are shown in Table 2.

Table 2: The length of the magnetic bra formed on the sleeve surface is as follows:
The average was 250 ttm in all cases.

When a multicolor image was formed by developing yellow, magenta, red, and black in this order under the above conditions, a multicolor image with sufficient density and good resolution was obtained, with no visible directionality of development.

Note that the process explained in FIG. 7 can also be realized by an apparatus as shown in FIG. Here, the same parts as in FIG. 6 are indicated by the same symbols. This apparatus is characterized in that multicolor development can be performed during one rotation of the image forming body. That is, the negative color image is between the charger 21A and the image exposure device 2.
6A, and after this is developed by the developing device A, a similar process is immediately executed by the charger 21Ill, the image exposure device 26B5, and the developing device n, and subsequently for other colors.

The present invention is particularly effective in a multicolor image forming apparatus as shown in FIG. 6 or FIG. 8, and completely prevents toner of different colors from getting mixed into the developing device during the developing process or scattering. An image with good color reproduction +1 can be obtained.

The present invention can also be preferably applied to an apparatus capable of forming a multicolor image on a photoreceptor by performing image exposure once. The apparatus performs multicolor image formation as described below using a photoreceptor preferably provided with an electrically conductive member, a photoconductive layer, and an insulating layer including a filter layer consisting of a plurality of different filters.

That is, by applying electrical charge and imagewise exposure to the surface of the photoreceptor, an image is formed based on the charge density at the interface between the insulating layer and the photoconductive layer, and by exposing the entire surface of the image forming surface to specific light, the image of the photoreceptor is A potential pattern is formed on the filter portion, and the potential pattern is developed by a developing device containing toner of a specific color to form a monochrome toner image. Next, after smoothing the potential pattern by charging, a potential pattern is formed by exposing the entire surface with light that is different from the previous one, and development is performed using a developing device that stores toner of a different color from the previous one. A second color toner image is formed. Thereafter, potential smoothing, total 7M exposure, and development are repeated as many times as necessary. In this development, an image forming method using a non-contact developing means is used at least from the second time onwards. As a result, toner of different colors adheres to each filter portion of the photoreceptor, forming a multicolor image (Japanese Patent Application Nos. 59-83096, 59-187044, 5
(See Nos. 9-185440 and 60-229524).

According to this multicolor image forming apparatus, only one image exposure is required, so there is no risk of color shift occurring.

In addition, the photoreceptor has a structure in which a filter is provided on the conductive substrate side, and image exposure and full-surface exposure are performed from the filter side (Japanese Patent Application No. 1983).
-199547) and its f1!2 configuration (patent application No. 1983)
-201084).

Further, the photosensitive layer is not limited to a single layer, and may have a functionally separated structure consisting of a charge generation layer and a charge transfer layer. (Tokugan Sho 6
0-245178) In addition, the photoreceptor has a color separation function in the photosensitive layer (Japanese Patent Application No. 5
9-20 +, No. 085, patent application No. 60-2451, 7
No. 7) Can be structured.

[Effects of the Invention] As is clear from the above description, according to the developing method of the present invention, it is possible to obtain images that have sufficient image density, high resolution, and in which the directionality of development is not visible. effective. In particular, when the present invention is applied to multicolor development, it is possible to obtain both images with good color reproducibility as well as the effect of preventing toner contamination.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a developing device suitable for the developing method of the present invention;
Figure 2 is an enlarged sectional view near the sleeve surface, Figure 3 (a)
is a diagram showing the main part of the layer forming section in the developing device of FIG. 1,
Figure 3 (B) is a diagram showing the characteristics of layer formation, Figure 4 (A) is a perspective view of the stirring member, Figure 4 (B) is a front view of the stirring member,
FIG. 5 is a sectional view of a main part of an image forming apparatus according to an embodiment, FIG. FIG. 7 is a flowchart showing a multicolor image forming process, and FIG. 8 is a sectional view showing another example of the structure of the multicolor image forming apparatus. 1... Image forming body 3... Developer transport carrier (sleeve) 4... Magnetic roll 5... Layer forming member 7.8... Stirring member 7a
, 7b, 7C, 8a18b, 8C-- Stirring blade h...
・Toner supply container 1=1...Bias power supply 15...
・Development area IN...Image input section 2h...
Image sensor 26...Laser optical system 22, A, B
, C, D...Developing device 16...Exposure lamp order...
Transfer pole 34... Separation pole 31... Fixing device
Tr<...Image processing unit I...Cleaning device 2+, 21A, 21B, 2IC, 2h)...Charger 26A, 26B, 26C', 26T)...
Image exposure device Applicant: Konishiroku Photo Industry Co., Ltd. Fig. 1 R Mini - Fig. 3 (A) Fig. 3 C Exit) Door t Go °F! ! (-1 Figure 4 (I) Figure 5 Figure 6 (a)

Claims (1)

[Claims] (1) An electrophotographic developing method in which a magnetic brush of a two-component developer having a carrier and toner is formed on a developer transporting member, thereby developing a latent image on an image forming member, the developing method comprising: 1. An electrophotographic developing method characterized by having a rotating magnetic roll therein, keeping the magnetic brush and the image forming body out of contact, and satisfying the following formula. |(V_s_l−ωmh/3)/(Vd)|≦10|(
V_s_l−nωmh/3)/(Vd) | m_t≧0.
4 [mg/cm^2] Here, V_s_l is the linear velocity of the developer conveying member, n is the number of magnetic poles of the magnetic roll, ωm is the rotational angular velocity of the magnetic roll, h is the length of the magnetic brush, and Vd is the image forming body. The linear velocity m_t represents the amount of toner adhesion per unit area of the developer conveying member, and V_s_l and ωm are positive when they are in the same direction as the movement of the image forming member.